The interior of a pressure contact electrical terminal fitting is provided in a unified manner with pressure contact blades which define a groove therebetween. When an electric wire is inserted into the groove, the blade edges cut through the insulating covering of the electric wire and thereby make contact with the conductive core. In this manner, the pressure contact terminal fitting allows electrical contact between the electric wire and the terminal fitting. Such a pressure contact terminal fitting has the advantage of not requiring a shaving process for exposing the end of a core wire, which is required in the case of a terminal fitting in which the core wire is connected by crimping or soldering of a barrel.
FIG. 6 of the accompanying drawings shows a conventional pressure contact terminal fitting. A terminal fitting 40 has two pairs of pressure contact blades 45, formed anteriorly and posteriorly, and located inside a pressure contact member 41 whose upper face is open and forms a channel, facing side walls 42 thereof being sheared out so as to form a pair of mutually facing protruding members 43 which constitute the pressure contact blades 45. A pressure contact groove 44 is formed between the protruding members 43. The reason for providing two pairs of blades 45 is that the core wire normally consists of a plurality of thin intertwined wires, and providing only one pair of blades 45 can result in the core wire becoming unwound after making pressure contact, and this can cause the core wire to escape the groove 44 or otherwise reduce the electrical contacting force. If two pairs of pressure contact blades 45 are provided, the unwinding and poor contact are prevented from occurring, and the reliability of the electric contact increases.
In the pressure contact terminal fitting 40 having the configuration described above, the protruding members 43 which form the pressure contact blades 45 are sheared out from the side plates 42. However, the sides walls 42 are formed in a unified manner with barrels 46 which serve to fix the electric wire by being crimped around the posterior end of the pressure contact portion of the electric wire. Consequently, due to the barrels 46 being crimped, the side walls 42 have a tendency to change shape by bending, resulting in a slight change in the width of the pressure contact groove 44. This adversely affects the reliability of the pressure contact.
FIG. 7 shows a different type of prior pressure contact terminal fitting. A terminal fitting 50 has two pressure contact blades 53 formed anteriorly and posteriorly by shearing out of a base plate 54 of a pressure contact member 51, the blades 53 having pressure contact grooves 52 formed thereon. In this configuration, since the pressure contact blades 53 are cut out from the base plate 54, even if the side walls 55 bend in accompaniment with the crimping by the barrel 56, the accuracy of the dimension of the pressure contact grooves 52 remains unaffected by the bending, resulting in a higher reliability of contact compared to the terminal fitting 40 of FIG. 6. However, since the two pressure contact blades 53 are sheared out from the base plate 54, there is a problem in that the total length of the base plate 54, that is, the length of the terminal fitting 50, becomes larger than that of the other prior terminal fitting 40.
Both the terminal fitting 40 of FIG. 6 and the terminal fitting 50 of FIG. 7 have their own advantages and shortcomings; consequently a further improvement seems desirable. The present invention has been developed after taking the above problems into consideration, and aims to maintain a short length while achieving a highly reliable pressure contact.